A good trend following system will keep you in the market until there is evidence that the trend has changed.

Trading decisions should be made as unemotionally as possible.

When things aren't going right, don't push, don't press.

I learned to avoid trying to catch up or double up to recoup losses. I also learned that a certain amount of loss will affect your judgment, so you have to put some time between that loss and the next trade.

Trade small because thats when you are as bad as you are ever going to be. Learn from your mistakes.

You should always have a worst case point. The only choice should be to get out quicker.

Trading has taught me not to take the conventional wisdom for granted. What money I made in trading is testimony to the fact that the majority is wrong a lot of the time. The vast majority is wrong even more of the time. I've learned that markets, which are often just mad crowds, are often irrational; when emotionally overwrought, they're almost always wrong.